Directive radio repeating system



Feb. 14, 1928. 1,658,851 DE LOSS K1 MARTIN DIRECTIVE RADIO REPEATING SYSTEM Filed Dec. 28. 1921 firs, firs l l 1 5 A b A 1 4 05610 1 ,gr azw w ATTORNEY Patented Feb. 14, 1 928.

wm -w A 1,658,851 PATE T; OFFICE? DE Loss Q'MAETIN, oE ORANGE, NEW J Es xl As'sIGNoE TO AMERICAN TELEPHONE I AND TELEGRAPH COMPANY, A- ooEPo ArIoN on NEW YORK.

DIRECTIVE E mo EEPEA'E N SYSTEM.

- A licationfiled December 2 ,1921.-Saa1=m. 525,4i4.1

This invention relates to directive radio repeating systems and especially totha-t type of system inwhich the transmitted amplified waves have*a difi'erent frequency from-the receivedwavesfl p In the copending applications of Espenschied and Martin, Serial Nos. 525,442 and 525,443, both filed December'28, l92l,there is disclosed a plurality of means for relaylll ing radio signals in which the frequency of the received signals is changed at the repeating stations, so that transinlsslon is effected at a different frequency from reception. One ofthe objects of the present invention is to provide in a directive radio repeating station means for supplying 'the beating oscillations to each modulating circuit of the said station, whichmeans are characterized by an arrangement for ensuring synchronism of the oscillations "impressed upon each modulating circuit.

Other objects of this inventlon will be apparent from the following description when read in connection with the attached drawing of whichlFigure' l shows a plurality of antennae indicatingan array, each antenna having its amplifying and frequency changing circuit and a source of oscillations individual thereto, the said oscillators being connectedtoa common. circuit ior synchronizing purposes; Fig. '2 represents a similar antenna array with individual amplifying and frequency changing circuits,but.havinga single source of beating oscillations commonto all the local amplitying circuits; and Fig. 3 indicates a similar antenna array in which the beating oscillations are supplied from a master antenna through the ether to each antenna for im I pression upon its individualamplifying and frequency changing circuit.

[n Fig. 1, X,, X and. X represent three loop antennae constituting a part of a single array intended for the reception and transand frequency changing circuit by a transformer, such as T associated with the antenna X Since all of the local circuits aresimilar, the description will be confined to that one associated with the .antenna X local circuit, connected to the antenna mission. of signals, but it is to be understood vice PS the band X, by the transformerTb comprises a network *N designedto balance the antenna X a phase shifting device. PS a band filter F designed to transmit the frequenclespresent in the received band-of oscillations, an am- 'plifier A,, which may be of single-stageor 1nulti-stage type, amodulator M,, which is designed tobeat together the oscillations of i the received band and also unmodulated oscillations from the local source 0 a second hand filter F designed to transmit either the upper or lower side band frequencies resulting from the saidmodulation process, a high power amplifier A a third bandfilter F having thesame characteristic as F, and a phase shifting device PS, designed to control the phase of the current applied'to the loop X of .t-he'antenna array A for transmission therefrom. *Each localcircuit'has connected thereto a source of oscillations,O O and 0 which are designed to produce oscillations of the same frequency.

In order to insureidentity of frequency of the oscillations produced by each local oscillater, a synchronizing circuit extends between the adjacent osclllators and thus connects all of them*together. 'This circuit is I not a power supply circuit, but .servesto transmit only such currents between the various oscillators as result from lack of synchronism and which 1sjnecessary'tof 'estore synchronism to the system of oscillators. Phase shifting devices may, if neces sary, be inserted between each oscillator and i its point of connectionwith the common circuit, in order to'correct for phase displace- The mode of operation of the arrangement in which the invention is embodied is as follows: Current of the signaling frequency will be set up in each of the antennae X X and X, as a result of the wave across the array. in the loop X for example, will be trans mitted by the transforiner T to the local circuit, traversing the phase shifting depassage of a based upon "the carrier frequencyf will be modulatedat M by current of a frequency The current set upv V filter F and the low power amplifier A,. This current, which for example, may comprise a band of frequencies As a result, the band of frequencies wh h will be a d pon anew carrler freg transmitted through the band filter F,, amplified by the power amplifier A trans- .mitted through the filter F and given the proper phase displacement the phase shifting device Pb, before radiating from the antenna X,. Similar action is taking place simultaneously in each local circuit connected with and individual to'thc other antennae of the array, but the phase displacen'ient of the current in each local circuit, produced by the phase shiftingdevices of each local circuit, may differ in order to obtain the desired directional characteristic for the array. \Vhen, however, the desired directivity of reception and transmission has been attained by a definite setting of the phase shifting devices it will continue un changed so long as synchronism is maintained between the various oscillators of the system.

The arrangement shown in Fig. 2 is, in general, similar to that shown in Fig; 1

with the exception that a single source of Phase shifting devices PS, PS andPS" areinserted on each of said branch circuits, between the common circuit L, and each local circuit for the purpose of compensating for the phase displacement of the beating oscillations in each branch circuit due to the transmission of high frequency currents over the common transmission line L In this manner syncln'onism'is ensured for-the beating oscillations applied to the modulators of each local circuit of the entire array.

The arrangement shown in Fig. 3 differs in principle from that shown in Fig. 2 in that the beating oscillations are supplied from acommon source to each lo -al a'mpli fying circuit through the other instead of over a metallic circuit. as in Fig. 2. In Fig. 3, X X X, and X, represent loop antennae designed forthe reception and transmission of the signal ilrequencies andrepresenting part of an array. Each antenna is connected with its individualamplifying and frequency changing circuit by means of a transformer, such as T, shown in connection with the antenna X Each local circuit has also connected thereto another antenna, such as A, which is designed to receive the beating oscillations from a common source of osc1lla-' tions, represented by the antenna X connected with the oscillator O, and to impress the beating oscillations upon the local circuit.

ii hen signaling oscillations of, for example, the frequency 7,, together with the band of frequencies superimposed thereon,

are received by the antenna X,, they will be impressed by the transformer T upon theiuput branch of the local amplifying circuit; These received signaling oscillations will be transmitted through the phase shifting device PS, and thence through the band filter F, designed to transmit this band of frequencies. The beating oscillations radiated by the antenna X will be received by the antenna X tuned to this frequency, and also by other similar antennze of the array. These oscillations will be transmitted t irough the filter F and impressed upon the amplifier A,-together with the band of sinnaling oscillations which have passed through the band filter F,. The amplified oscillations of both the signaling and the beating frequencies vill be modulated by the modulator M,, and the resultant bands of oscillations oli, ior example, the frequencies represented by f, will be amplified by the am pliiier A. These bands of frequencies will be impressed upon the band filter F, which is designed to transmit only one band as, for example, F,F,. Oscillations of these frequencies will be given thoproper phase displacement by the phase Shifting device PS and will be transmitted from the au tenna X Th-eaction taking place in the other local circuits connected with the an tennae X X X etc. will be similar to that taking place in the local circuit connected with the antenna vX, excepting, as pointed out particularly in connection with Fig. 1, that the phase displacement of the oscilla tions in the local circuits may differ.

Although in the forms in which the invention has been disclosed balanced loop antennaehave been shown, it is to be understood that the invention is not limited to a particular type of antenna structure but it may be used in connection with any type of antenna structure or any type of balancing such as the balanced ground-vertical antenna structure shown ,iu the copending application of Espenschied and Martin Serial No. 525,442. It will be seen that by means of the. arrangements heretofore described I have provided, in a radio repeating system having directive characteristics, means for supplying the beating oscillations necessary for changing the frequencies of the currents transmitted through such repeating stations, which means are designed to produce synchronismof the oscillations applied to each of the modulating circuits of the system.

Although this invention has been described as embodied in a certain form and arrangement ofparts, it is to be understood that it is capable of embodiment in other and more widely varied forms without departing from the spirit and scopeiof the appended claims. Y I What is claimed is:

1. In a radio repeating system, the combination with a directive antenna array comprising a plurality of antennae symmetrically arranged, of a plurality of modulatingcircuits individual to and connected with each of said antennae, and means common to all of said circuits to apply synchronous beating oscillations thereto.

2. In a radio repeating system, the combination with a directive antenna array comprising a plurality of antennae symmetrically arranged, of a plurality of modulating circuits individual to and connected with each of said antennae, a central source of beating oscillations connected with each of said modulating circuits, and means con nected with each of said modulating circuits to insure synchronism of the beating oscillations in each of said circuits.

3. In a radio repeating system comprising an antenna array, comprising-a plurality of antennae symmetrically arranged, amplifying circuits having phase controlling means and frequency changing means associated therewith individual to and connecteclvwitheach-of said antennae, the method of repeating, which consists in receiving oscillations of definite frequency, impressing upon its amplifying circuit the oscillations received by each antenna, beating in each frequency changing means the received oscillations to"- gether with oscillations of different freuenoy, automatically maintaining in sync ronism the modulating oscillations supplied to each frequency changing means and radiating the oscillations of the frequency resulting from modulation.

4. In a directive radio relay characterized by the reception and transi'nisslon of the same signahng channel at different frequencies, the method of modulation, which con-,

sists in transmitting the modulating frequency from a central source, correcting the phase ofthe modulatingoscillations, supplied to each modulator ofthe system and a beating the received frequency with the modulating frequency from the said central source.

' 5. In a directive radio signaling system,

the combination with a plurality of antenme symmetrically spaced constituting an antenna array .of a plurality of frequency translating circuits, each individual to and oonnected'with one of said antennae, each translating circuit incluc'ling a modulator means to maintain in synchronism and phase all of the said oscillators.

In testimony whereof, I have signed my I name to this specification this 27th day of December, 1921.

DE LOSS K. MARTIN. 

